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Diffstat (limited to 'lib/Transforms/Utils/LowerSelect.cpp')
-rw-r--r-- | lib/Transforms/Utils/LowerSelect.cpp | 105 |
1 files changed, 0 insertions, 105 deletions
diff --git a/lib/Transforms/Utils/LowerSelect.cpp b/lib/Transforms/Utils/LowerSelect.cpp deleted file mode 100644 index e2940c2727..0000000000 --- a/lib/Transforms/Utils/LowerSelect.cpp +++ /dev/null @@ -1,105 +0,0 @@ -//===- LowerSelect.cpp - Transform select insts to branches ---------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This pass lowers select instructions into conditional branches for targets -// that do not have conditional moves or that have not implemented the select -// instruction yet. -// -// Note that this pass could be improved. In particular it turns every select -// instruction into a new conditional branch, even though some common cases have -// select instructions on the same predicate next to each other. It would be -// better to use the same branch for the whole group of selects. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Transforms/Scalar.h" -#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h" -#include "llvm/Function.h" -#include "llvm/Instructions.h" -#include "llvm/Pass.h" -#include "llvm/Type.h" -#include "llvm/Support/Compiler.h" -using namespace llvm; - -namespace { - /// LowerSelect - Turn select instructions into conditional branches. - /// - class VISIBILITY_HIDDEN LowerSelect : public FunctionPass { - bool OnlyFP; // Only lower FP select instructions? - public: - static char ID; // Pass identification, replacement for typeid - explicit LowerSelect(bool onlyfp = false) : FunctionPass((intptr_t)&ID), - OnlyFP(onlyfp) {} - - virtual void getAnalysisUsage(AnalysisUsage &AU) const { - // This certainly destroys the CFG. - // This is a cluster of orthogonal Transforms: - AU.addPreserved<UnifyFunctionExitNodes>(); - AU.addPreservedID(PromoteMemoryToRegisterID); - AU.addPreservedID(LowerSwitchID); - AU.addPreservedID(LowerInvokePassID); - AU.addPreservedID(LowerAllocationsID); - } - - bool runOnFunction(Function &F); - }; - - char LowerSelect::ID = 0; - RegisterPass<LowerSelect> - X("lowerselect", "Lower select instructions to branches"); -} - -// Publically exposed interface to pass... -const PassInfo *llvm::LowerSelectID = X.getPassInfo(); -//===----------------------------------------------------------------------===// -// This pass converts SelectInst instructions into conditional branch and PHI -// instructions. If the OnlyFP flag is set to true, then only floating point -// select instructions are lowered. -// -FunctionPass *llvm::createLowerSelectPass(bool OnlyFP) { - return new LowerSelect(OnlyFP); -} - - -bool LowerSelect::runOnFunction(Function &F) { - bool Changed = false; - for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) - for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { - if (SelectInst *SI = dyn_cast<SelectInst>(I)) - if (!OnlyFP || SI->getType()->isFloatingPoint()) { - // Split this basic block in half right before the select instruction. - BasicBlock *NewCont = - BB->splitBasicBlock(I, BB->getName()+".selectcont"); - - // Make the true block, and make it branch to the continue block. - BasicBlock *NewTrue = new BasicBlock(BB->getName()+".selecttrue", - BB->getParent(), NewCont); - new BranchInst(NewCont, NewTrue); - - // Make the unconditional branch in the incoming block be a - // conditional branch on the select predicate. - BB->getInstList().erase(BB->getTerminator()); - new BranchInst(NewTrue, NewCont, SI->getCondition(), BB); - - // Create a new PHI node in the cont block with the entries we need. - PHINode *PN = new PHINode(SI->getType(), "", NewCont->begin()); - PN->takeName(SI); - PN->addIncoming(SI->getTrueValue(), NewTrue); - PN->addIncoming(SI->getFalseValue(), BB); - - // Use the PHI instead of the select. - SI->replaceAllUsesWith(PN); - NewCont->getInstList().erase(SI); - - Changed = true; - break; // This block is done with. - } - } - return Changed; -} |